Current and potential measuring transformer



0a. 17, 1933. K. BAHRMANN 1,930,604

CURRENT AND POTENTIAL MEASURING TRANSFORMER Filed D80. 13, 1930 ,fiLvezzt l r W PM? MZ'W'S.

' Patentea Oct. 17, 1933 f kai'iaensue-560i, Dateline;

. potential nieajsu jing'mti'ansfbr mer'. f l It' has Ire dy' b e1} proposed to so; constr et poter'itiaitiansformer'sfaslea ddi s thzitQthe e611? 5 ducter" jqariyiiig' the 'h igliesflpbtfehtigal',jeuri ent passesfa xia lly through theipete'ritial transformer; While between the poles; namely; the lad-thifcjifih' conductor and the iron core surrounding it, coin '3 The pi'eseiit inyei tienj relates ,to a cuif'rerit an'd pul'sory potential graduation takes'pl ece by. m ofi tliehigh' potential wi r diiigjepiiduetivel y con necting the two pqles together. Otherwise cun ent' and potential i n ror'mers havg ways egn separately eonst iictedappai'atus.

isto provideja compact eoi ilqined a I tential measuring transformer ilAceording to the jinx/exiting; 1 I

combine currentand pdte'ntial'ti e {orme rsintq one unit in such manner thatflby'a; Oidingldupli;

ht and p015 catel constructive partstend "usingfihe lpotentie 1 transformer as i sulatiqn f brjthe eurrent'ftiens former, it becomes"evenexteiilally, apparatus 6f minimum dimensiens. II 1'fGh1;S',t he ma'gz e t sys ftj miri'fllienced bythe-ciiirent i'spe'iper diciilzir t9 1 .25 the system i influenced by? the potential "and "siirrour'i'ds' the lat-ten At the same time, a' clclording to the' inventidn, theinductiijn'sys'tem (Sari be used? asalead-ii with conti'elled pOtntial-distpibgtioiri irthe drawing;jare shbwfiexamplesof e'Xetn -i Figure r news i'h vertieaiei'diss s eetionia'n system a 'sfin Figure 11.1. 1 p 7 Figu 3 isadiagrammaticshgwiiig h the -ci'rcuit'of tine ofgthe'lgw pbtentiel wiz qings.

eabh vertieallimb of which cat 'es si tran'sformer V (I v I ir g the iro cere Coneent 'ically-disQoSeQgbOgij ahrmanm lnresden, Germany, "assi'gfior 1:01? I Ko'ch & Sterzel; Aktiengesellschaft, Dresden,

v ficxma yi a c mpa y of Germany fThe prineipal bbjectof eirciiits is entii elyfiindependnt with iel' atibzi te ,o rltakes it within itself."., The cohau toriijppfqgh the, insulating 'meme r i4} is me seeqndary Uwind- .i9 V bein .s ichthat aitransfeimer isproduedwhich. does nqt, have the iisiiel rectengulgr i 'cloised 001i? "the winding as spawn in Fig.3. In Eig u're Zqgh 1 lqw potential-winding 17 (pdtential transformer i is disp'osed concentrically about the highpbtii- A .windi 13.-an ;ue dfl e' at 14 ali i 'bejenrmentioned with regard: to Figure 1, The! 19w potential winding 2'4 lfipotntial" tr.hsfoi'mer)}.- issimilai'lyvdisposedwith IQlfitiQIitQ the higlfpqtential' winding; 23. fl Each of these, low potential windings is icl'csed thrbi gh'a circuit inebrpqratirig Menage measuring instrument; and. each 9: sg icl the other lhe' lowpotei tial windings lTand 19 a e, in ommon with the irbr QOreiB lsurtOuntied bye; slotted flange-like casing 20 which; in theta-Se of high current strengths; is pieqgced framing-1 'n 'eg ietij materiaLaiidcan serve -as e leadfln :flangei, Thus a single bar leed-infeumier tltrans 755 fdrmer is cerjlibineq with'lal'pg tntiel'tfe hsi'ei h eif in which the megnetic system influenced fbyf the;

- current (is rra'nge'd perpendicil larly ltd"thetf in fluenced by thelpotential, and surr'ouriiis the letter .elir 'nt 'rflp'ws', passes; he r gaxiall th pugh the current transformer {173,- 1 7 'and 'the eui renttransformer coz e 1L8 which iset earth mgi i epndiieting lead to meconsumefl The trans V fg imer core 12 is ef singlef o bar-sliapevei d'fis completely enclosed'in itsrve itic'al direetion byzthe b' m -i i P m i i .58m. Wi e j "wouage t 'ansfdrineml; the; axfrz'aQrige zinei t path.

Positive eonti ble f the 'pbinmi 'a tteined s nce thel d mii em n 'fi of the i -h potenti i md;

if the insulator is provided with conductive elements which are only coupled capacitatively to the conductor supplying the potential. In the latter case the voltage may be adjusted as desired in such manner that there is no positive control thereof.

The low potential winding 1'7 of the voltage transformer is, as above-mentioned, concentrically wound about the centre of the high potential winding 13 and is also disposed outside the insulator 14. This winding 17 is of a length which corresponds to the measuring capacity within the casing 20. Concentrically disposed around the winding 1'? and also located within the casing 20 is an annular split iron core '18 as in Figure 1. This core carries a winding 19, said winding. being composed of turns arranged around the cross sectional periphery of said ring; The end turn of this winding 19 is not conducted directly within the casing 20, but, as shown, is led back to the commencement of the winding, from which it is connected to the ammeter or equivalent current measuring instrument.

In Figure 2 is shown a multiple conductor loop current transformer, in which the systems are duplicated. The iron core 21 of the potential transformer is closed, and parallel thereto are the primary windings 22 of the current transformer. The two high potential windings l3 and 23 of the potential transformer are surrounded by their lowpotential windings ,1'7 and 24, the two low potential windings being either connected in parallel or connected separately with the users. The commencement of each of the windings 13 and 23 is electrically connected with one of the vertical arms of a rectangular iron core 21, the latter being supplied with the initial potential through the leads 22. The terminating ends of the respective high potential windings 13 and 23 are grounded through the casing 2'7 and the current passing through the apparatus is divided through the respective portions of the core 21 surrounded by the windings 13 and 23. The iron core surrounding the voltage secondary windings 1'7 and 24 andcarrying the winding 26 feeding the current measuring instrument A, is of unitary construction. In the construction shown in Figure 2, the core 25 is of rectangular or similar form and is provided with a central limb. Each limb of the iron core can be surrounded by a ring shaped current transformer core with low potential winding, in the manner shown in Figure 1, one of which can serve for measuring purposes and the other for the supply of relays, It is, however, also Possible by means of a jacket core 25, for example in the shape of an eight, to let both limbs of the potential transformer core 21 be surrounded when, in case of necessity, the central bar of the current transformer core, which carries thev low potential winding 19 of the current transformer, is slit.

Preferably, here the known windings 26 are used on both yokes of the jacket core for the purpose of increasing the output of the transformer. It is also easily possible to use a number of such current transformer iron cores when user current circuits independent of each other are to be supplied. The whole doublelead-in current and potential transformer is again fastened on an earthed supporting flange 2'7. With both forms of construction, the high potential winding of the potential transformer embedded in the insulating material, serves for the compulsory potential control in or along the insulating material between the iron core which'is on the primary conductor potential of the transformer, and the low potential winding of the potential transformer, or current transformer, and the earthed flange.

What I claim and desire to secure by Letters Patent of the United States is:--

1. The combination with a conductor, of a measuring transformer apparatus comprising a core surrounding the conductor, a primary winding surrounding said core, said primary winding being electrically connected with said conductor and said core, a secondary winding surrounding said primary winding, a grounded casing enclosing said apparatus, said primary winding being electrically connected to said casing whereby compulsory potential control is provided.

2. The combination with a conductor, of a measuring transformer apparatus comprising a core surrounding the conductor and electrically connected thereto, an insulating body surrounding said core, a primary winding embedded in said insulating body, said primary winding being concentric with said core and of layerwise construction, the layers decreasing in width from the inner layer to the outer layer, the inner layer being electrically connected to said core and the outer layer being connected to ground and a secondary winding surrounding said primary winding. a

3. The combination with a conductor, of a measuring transformer apparatus comprising a core surrounding the conductor and electrically connected thereto, an insulating body surrounding said core, a primary winding embedded in said insulating body, said primary winding being concentric with said core and of layerwise construction, the layers decreasing in width from the inner layer to theouter layer, the inner layer being electrically connected to said core and the outer layer being connected to ground and a secondary winding surrounding said primary winding, said secondary winding being arranged in a plane perpendicular to said core.

. 4. The combination with a conductor, of a measuring transformer apparatus comprising an open rectangular core electrically connected to said conductor, opposite pairs of legs of said rectangular core being surrounded by an insulating body, a primary winding embedded in each of said insulating bodies, each of said primary windings being concentric with the respective leg of the core and of layerwise construction, the layers decreasing in width from the inner layer to the outer layer, the inner layer being connected to said core and the outer layer being connected to ground and a secondary winding surrounding each of said primary windings.

5. The combination with a conductor, of a measuring transformer apparatus comprising an open rectangular core electrically connected to said conductor, therconductor being formed into loops extending parallel with said core, an insulating body surrounding each leg of anopposite pair of legs of said rectangular core, a primary winding embedded in each of the respective insulating bodies, the primary windings being concentric with the respective legs of the core and of layerwise construction, the layers decreasing in width from the inner layer to the outer layer, the inner layer of each being connected to said core and the outer layer of each being connected to ground, and a secondary winding surrounding each of said primary windings.

6. The combination with a conductor, of a. measuring transformer apparatus comprising an I legs of said rectangular core being surrounded by an insulating body, a primary winding embedded in each or the insulating bodies, each of said primary windings being concentric with the respective leg of the core and of'layerwise construction, the layers decreasing in width from.

being electrically connected to said core and the outer layer being connected to ground and the inner layer to the outer layer, the'inner layer 7 a secondary winding surrounding each of said primary windings, said secondary windings being arranged in a plane perpendicular to the legs of said core which carry the primary windings.

KARL BAHRMANN. 

